1. Field of the Invention
The present invention relates to hydraulically and volumetrically dispensing fluid. More particularly, the present invention relates to systems and methods for dispensing a known volume of a target fluid, whether liquid and/or gas, through the use of a hydraulic system.
2. Background and Related Art
Historically, a variety of techniques have been employed to dispense materials. Such techniques have included pushing a material through a flexible conduit, using a water control valve to provide pressure to a material, employing a water control valve to dispense the material, and using a hand-held applicator that accommodates a syringe, each of which will be discussed below.
A first technique employs a flexible conduit through which a material is pushed. In U.S. Pat. No. 5,878,921, a grout delivery apparatus and method is disclosed for delivering grout through a flexible conduit from a bulk supply of grout to a hand tool. The bulk supply of grout is held in a hopper, which feeds the grout under gravity to a pump. The pump is driven by an electric motor, which receives its electrical energy through a controller. The controller is adjustably preset to control the electric motor as a function of the individual settings on a malfunction switch operable by the worker. The switch can either be mounted on the hand tool and directly wired to the controller or incorporated into a remote transmitter, which transmits the particular switch position to a receiver on the controller. Similarly, U.S. Pat. No. 6,268,000 discloses a device for dispensing pastry dough, frosting, or icing from a cartridge. The device has a cartridge container and a hand-held gun. An electric motor having a piston is coupled to the cartridge container. The piston acts on a plunger of the cartridge to apply pressure on the pastry dough, frosting, or icing to permit the pastry dough, frosting, or icing to move to the gun to be dispensed. The technique in both disclosures requires a material to be pushed through a tube or flexible conduit in order to dispense or apply the material. One disadvantage of this technique is that residue of the material is typically left behind on the inside wall of the tube or conduit that must be cleaned. This requirement of cleaning the tube or conduit can be time consuming and the residue indicates a waste of a portion of the material.
In a second technique, a water control valve is employed to provide direct pressure to a material that is being dispensed. This technique is disclosed in U.S. Pat. No. 6,041,977, which discloses a dispensing system for dispensing decorating materials, such as frosting. The dispensing system includes a dispensing tube having the material to be dispensed and a water-operated piston. Application of water under pressure to the dispensing tube results in the dispensing of the material through a decorating tip. The water pressure applied to the dispensing tube is controlled and regulated through the utilization of a control valve assembly having a flow stop valve and an on/off valve. Water applied to the control valve assembly is pressure regulated and filtered. While this technique reduces the requirement for cleaning and reduces the amount of material wasted, it requires the constant pressurizing of water and typically proves to be awkward in use of some applications.
A third technique employs compressed air to dispense a material. This technique illustrated in U.S. Pat. No. 5,964,381, in which a piston is disposed inside a tube having an inner cross-sectional size and shape uniform along its length. The tube has an open end. The piston is free to move literally inside the tube and preferably may move out of the tube through the open end. If the tube is cylindrical in shape it has a constant inner diameter. The open end of the tube is neither tapered nor flaring. Liquid samples are aspirated into the device by pulling the piston back. The sample is then ejected by accelerating the piston to a minimum velocity to force the liquid sample out of the open end of the tube. The velocity of the sample is sufficient to render negligible effects of surface tension forces. The volume of the liquid sample dispensed is determined by the inner diameter of the tube and the piston displacement. Accurate positioning of the piston provides samples of accurate volumes. This technique can provide an accurate delivery of a material as long as the viscosity of the air does not change. However, a change in atmospheric temperature and/or pressure affects the technique by requiring the system to be adjusted for each given atmospheric modification. As such, this technique can prove to be time consuming, as it requires the calibration to the various surrounding conditions.
Another technique is provided in U.S. Pat. No. 5,630,527, which discloses a fluid dispenser system, and method of use thereof, primarily in industrial applications requiring the dispensing of fluids, such as epoxies, silicones, adhesives, etc., allowing for very precise control of the volume of fluid extruded. The system comprises an ergonomic, hand-held applicator accommodating a conventional medical syringe, wherein the applicator is attached to an electronic control unit by a power cord. The applicator is provided with a stepping motor that drives a piston or screw a specific distance in response to an electronic signal generated by the control unit. Displacement of the piston or screw creates a positive pressure on a fluid contained in the syringe, thereby causing fluid extrusion from the syringe. While this technique can dispense a precise amount of material, the apparatus of the hand-held applicator can prove to be bulky and awkward to use.
Thus, while techniques currently exist that are used to apply or dispense a material, challenges still exist, including causing a portion of the material to be wasted, needing to clean the residue from the material after each use, requiring a calibration of the device for each surrounding condition, and other such challenges. Accordingly, it would be an improvement in the art to augment or even replace current techniques with other techniques.